1. Field of the Invention
This invention relates to building structures for housing machines used in industrial manufacture. In particular, the present invention relates to improvements in the industrial building structure system disclosed in my U.S. Pat. No. 3,961,712 for housing machinery, e.g., a paper machine, for use in a continuous process activity.
2. Description of the Prior Art
As was more fully described in my U.S. Pat. No. 3,961,712, industrial buildings for continuous process activity such as the manufacture of kraft paper, traditionally were constructed much larger than necessary to house the particular machinery itself. The oversized building dimensions were required to enclose a traveling crane and hoist system used to service the particular machine, such as replacing one of the paper dryers in a paper machine. These paper dryers can be 35 feet long, 6 feet in diameter and weigh over 50,000 pounds.
Newer industrial building concepts, such as disclosed in my earlier U.S. patent, involve tailoring the size of different sections of the building to accommodate the machinery of that section. In particular, for the dryer section of a paper-making machine, it is possible to significantly reduce the size of the enclosing building structure by eliminating the enclosed traveling crane system. Thus, the use of an external crane system, such as shown in my previous patent, allowed the size of the building enclosing the dryer section to be markedly reduced resulting in a building with a lower initial cost, with attendant savings in the usual operating costs, such as heating, lighting and maintenance.
The ability to reduce the size of the dryer section building is nevertheless limited by the need for enclosed areas along both sides of the machine to house the paper dryer drive motors, bearing lubrication apparatus, and associated equipment. These enclosed side areas are also used for the replacement of the felt rolls and general maintenance on the machine itself. The size of the felt rolls makes it imperative that sufficient space exists in at least one of the side areas for the passage of small material handling vehicles. Also, the side area is needed to remove torn paper from the dryer. This operation, called "spearing," is traditionally done by hand and requires the use of a long hooked probe operated by several men.
The width of modern paper making machines can exceed 35 feet in the dryer section, and the width of the building to accommodate the machine and side working areas can often exceed 90 feet. The difficulty and expense of erecting a structure to span the entire building width unsupported except at the sides has necessitated the utilization of intermediate support columns in the prior art structures. These intermediate support columns traditionally were placed immediately adjacent to the paper machine frame to minimize the length of the unsupported roof section. The placement of the columns closely adjacent to the machine frame often required the use of elaborate duct work to bypass the supports and complex coupling apparatus to connect the paper dryers with the drive motors. These drive motors were also located adjacent to the frame but had to be offset to clear the support columns.
Although the reduced size of the dryer building shown in U.S. Pat. No. 3,961,712 allows the use of a removable roof section to allow replacement of the cylindrical paper dryers from the top of the machine, the absolute size of these roof sections makes them extremely difficult to control when suspended by a crane mechanism except when the operation is carried out in an enclosed or semi-enclosed environment. These roof sections are typically made as light as possible, inasmuch as their weight governs the size of the supporting building frame structural members and thus the overall cost of the building section. The light weight of the sections coupled with the large surface area contributes to a sail-like effect even in light wind conditions, thereby complicating, and introducing a degree of danger to, the paper dryer removal operation.